Shrink couplings (also known as “shrink disks”) are widely used in drive trains to couple a rotating shaft to another component, such as a gearbox. In many conventional wind turbine designs, a shrink coupling is used to secure the main drive shaft (“low speed shaft”) to the gearbox. This coupling can be quite large, often weighing in the range of about 2,000 lbs, and various maintenance procedures require removal of the shrink coupling. For example, inspection or replacement of the low speed shaft seal (also referred to as the “front seal”) in the gearbox can only be accomplished with removal of the shrink coupling.
Modern wind turbines can be quite large, with many designs having a rotor height exceeding 100 meters, and maintenance of these wind turbines often requires the use of a large construction crane in order to repair/replace components in the turbine nacelle. Removal of the main drive shaft shrink coupling is an example of just such a procedure that, to date, typically requires a crane. The logistic requirements, turbine down time, and expense associated with this maintenance procedure can be tremendous.
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. However, the cost/benefit economics of wind energy is a constant consideration. The cost of producing the energy, including maintenance of the wind turbines, cannot outweigh the benefits. In this regard, the industry would benefit from improvements or advancements in wind turbine operation and maintenance that would reduce the requirements (and associated expense and logistical burdens) for an on-site crane in the performance of maintenance or repair work on the turbines.